The problem arises of useless purchases of shoes or at least the loss of money from them, particularly with the smallest sizes for children. Thus, a pair of shoes bought at the right size for the foot of an infant at a given time, will be too small one month later because for example the growth was somewhat more rapid during a given period. In any case, a child's foot grows by one size every three months.
One solution consists of course in getting shoes one or two sizes too large, but such a choice is undesirable because the child is poorly shod which can give rise as is now known to problems at the ankle particularly during the growth period. The effects are not immediately visible but appear with age.
Moreover, the infant will be uncomfortable during a period longer than the period in the course of which the shoe is perfectly fitted, which does not favor learning how to walk, for example.
Another problem also relates to the quality and sale. Parents which must regularly change the shoes of an infant are inclined toward those of low price. As the quality is generally proportional to the price, the foot can suffer from such shoes.
Purchasing a pair of high quality shoes can be envisaged by the parents more readily if the shoes remain usable for a long time. This fully justifies the present invention, which provides a shoe which can be lengthened and to if desired widened to cover at least one additional size.
There are known inventions which disclose means to adjust certain elements of a shoe, particularly U.S. Pat. No. 4,944,099 which provides giving a certain extensibility in length to a shoe. The style described could hardly be considered to be a shoe, because it comprises only an instep and an upper, independent of each other, connected by elastic lateral elements, but this application must be considered as forming a part of the prior art showing the need, even though it is not relevant to the present invention.
The sole comprises two separate and independent portions, secured respectively to the instep and the upper and connected by the cross member of elastic material so as to render the sole monolthic.
The wearer can thus slip on this shoe by compensating very slightly small variations in length, whilst having to put up with the corresponding compression due to the powerful elastic element, which is impossible to envisage for infants.
A modification provides a complete upper but the cutout is provided with an elastic filament, which is prejudicial to a good support of the foot and to permitting the creation of a closed shoe.
There is also known from U.S. Pat. No. 5,163,237 an assembly of insoles of variable height, combined with an internal envelope which is sewn to at least the edge of the shoe. This envelope comprises a portion which is trapped below at least one of the insoles. According to the number of insoles stacked below the envelope or above it, the interior volume can be varied according to the soles which are all above the envelope or all below or else connected on opposite sides of this envelope.
If this description discloses means to adjust in volume a portion of the shoe, more particularly a moccasin, which is to say a shoe without laces, there is provided no means to vary the length and/or width of the shoe. No means permits the modification in length or width of the sole and much less to vary the length of the assembly of the upper, which is to say the end, the instep and the rear quarter.
Certificate of Utility FR-A-2.660.166 discloses a shoe whose rear quarter is removable to prevent transforming this shoe from a low-cut to a high-cut, particularly applicable to a sport shoe. The rear quarter is fixed by rapid hooking means such as that sold commercially under the mark "Velcro". A supplemental tongue also secures the rear quarter to the instep, this instep being able to mask this tongue.
There is not found in this prior art any indication or means for variation of length and/or width of a shoe.